Wideband frequency multiplier particularly adapted for use in badge readers and the like
First Claim
1. A frequency multiplier including in combination the following structural elements:
- sawtooth signal generator means producing a sawtooth linear voltage with a frequency equal to the frequency to be multiplied, the magnitude of the sawtooth linear voltage varying between a reference magnitude and a maximum magnitude which is mathematically related to the frequency to be multiplied;
a storage device coupled to said sawtooth signal generator means for a storing voltage having a magnitude equal to said maximum magnitude;
a voltage divider coupled to said sawtooth signal generator means and said storage device, said voltage divider including a plurality of outputs, each of said outputs electrically manifesting a voltage magnitude which is a predetermined fraction of the maximum magnitude stored voltage stored by said storage device;
a number of comparators, each comparator being associated with one of the outputs of the voltage divider and coupled to said sawtooth signal generator means, each comparator comparing the instantaneous magnitude of the sawtooth voltage with the magnitude of the voltage manifested at its associated voltage divider output, each comparator supplying a first level signal when the sawtooth voltage is higher in magnitude than the magnitude of the voltage manifested at its associated divider output and, a second level signal when the sawtooth voltage is lower in magnitude than the magnitude of the voltage manifested at its associated divider output; and
logic circuit means, coupled to said number of comparators, said logical circuit means logically combining the signals from said number of comparators to provide an output signal the basic time-period of which is a given sub-multiple of the time-period of the sawtooth signal.
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Accused Products
Abstract
An improved wideband frequency multiplier characterized as follows: a saw-tooth signal generator supplying a saw-tooth wave having a frequency equal to the frequency to be multiplied, the level of the voltage wave varying between a reference level and a maximum which is related to the frequency to be multiplied; storage means for storing a voltage equal to, or closely approaching the maximum voltage value of the saw-tooth wave; a voltage divider having several outputs, each of which provides an output which is a given fraction of the stored voltage; a number of comparators each of which corresponds to and is coupled to an output of the voltage divider, each comparator comparing the instantaneous value of the saw-tooth voltage with the voltage supplied by the corresponding output of the voltage divider, and supplying a first level signal when said instantaneous value is lower than the voltage supplied by said corresponding output, and a second level signal when it is higher; and logical circuits combining the signals supplied by the comparators so as to give an output signal the frequency of which is a given multiple of the frequency of the saw-tooth signal.
A timing circuit for a badge reader, or the like where the data is magnetically NRZ recorded on, or in, the badge, or the like. The timing circuit employs a frequency doubler as generally described above. The timing circuit also utilizes at least one additional logic circuit. The timing circuit provides timing signals synchronized with the reading of the data from the badge or the like.
34 Citations
16 Claims
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1. A frequency multiplier including in combination the following structural elements:
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sawtooth signal generator means producing a sawtooth linear voltage with a frequency equal to the frequency to be multiplied, the magnitude of the sawtooth linear voltage varying between a reference magnitude and a maximum magnitude which is mathematically related to the frequency to be multiplied; a storage device coupled to said sawtooth signal generator means for a storing voltage having a magnitude equal to said maximum magnitude; a voltage divider coupled to said sawtooth signal generator means and said storage device, said voltage divider including a plurality of outputs, each of said outputs electrically manifesting a voltage magnitude which is a predetermined fraction of the maximum magnitude stored voltage stored by said storage device; a number of comparators, each comparator being associated with one of the outputs of the voltage divider and coupled to said sawtooth signal generator means, each comparator comparing the instantaneous magnitude of the sawtooth voltage with the magnitude of the voltage manifested at its associated voltage divider output, each comparator supplying a first level signal when the sawtooth voltage is higher in magnitude than the magnitude of the voltage manifested at its associated divider output and, a second level signal when the sawtooth voltage is lower in magnitude than the magnitude of the voltage manifested at its associated divider output; and logic circuit means, coupled to said number of comparators, said logical circuit means logically combining the signals from said number of comparators to provide an output signal the basic time-period of which is a given sub-multiple of the time-period of the sawtooth signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A frequency multiplier particularly adapted to respond to a variation in the pulse repetition rate between successive pulses of an input pulse train having a pulse repetition rate subject to variation, said frequency multiplier including:
- sawtooth voltage generator means responsive to said input pulse train having a repetition rate subject to variation, said sawtooth voltage generator means providing a sawtooth voltage waveform wherein the maximum voltage magnitude of each sawtooth bears a direct fixed mathematical relationship to the repetition rate of predetermined first and second ones of said pulses of said input pulse train;
voltage storage means coupled to said sawtooth generator means, said voltage storage means successively sensing and storing the maximum voltage magnitude of each successive sawtooth of said sawtooth voltage waveform; voltage comparison means coupled to sawtooth voltage generator means and said voltage storage means, said voltage comparison means successively comparing the successive magnitudes of the voltage stored in said storage means with the instantaneous voltage value of the sawtooth following in time the sawtooth whose maximum voltage magnitude is stored in said storage means; logical circuit means coupled to said voltage comparison means, said logical circuit means being response to said voltage comparison means to provide an output pulse train having a repetition rate bearing a fixed predetermined mathematical relationship with the pulse repetition rate of said input pulse train, whereby the pulse repetition rate of said output pulse train tracks the pulse repetition rate of said input pulse train. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
- sawtooth voltage generator means responsive to said input pulse train having a repetition rate subject to variation, said sawtooth voltage generator means providing a sawtooth voltage waveform wherein the maximum voltage magnitude of each sawtooth bears a direct fixed mathematical relationship to the repetition rate of predetermined first and second ones of said pulses of said input pulse train;
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16. In a reader for reading magnetically encoded data on a record medium, where the reading of the magnetically encoded data requires relative motion between the record medium and a reading means, and the relative motion is subject to wide variation in the rate of movement, the provision of a timing circuit responsive to data read by said reading means to provide timing signals bearing a fixed time relationship to the reading of said data, said timing circuit comprising:
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a logical AND circuit having at least a first input, a second input and an output; frequency doubler circuit means, said frequency doubler circuit means includes, an input for receiving an input pulse train having a pulse repetition rate subject to variation, a first output for providing an output pulse train having a pulse repetition rate bearing a fixed mathematical relationship with the pulse repetition rate of said input train, said frequency doubler circuit means further including additional means for providing a further pulse train having a pulse repetition rate bearing a second fixed mathematical relationship with the pulse repetition rate of said input train; a logical AND circuit having a first input adapted to receive signals representative of said data read by said reading means, a second input adapted to receive said further pulse train from said frequency doubler circuit means, and an output for providing said input pulse train to the said input of said frequency doubler circuit means; whereby said output pulse train constitutes said timing signals which are continuously synchronized with the reading of the encoded data from the record medium.
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Specification